Newbie question

Hi together,
I am new to codeigniter, but not new to php.
So I installed it, tried the first example from the tutorial, and it worked.

Now I walked through the second tutorial (that one with the news)
https://codeigniter.com/user_guide/tutor...ction.html

and at the end it says:
"Point your browser to your document root, followed by index.php/news and watch your news page."

But then I get a 404 error (produced by codeigniter).

Of course I controlled all files in the tutorial, but dont find the error.

How can I find out, where I made a mistake in the tuturial?
Is there somethink like a debug-modus?

Thanks in advance!
Marco